I've experienced this with many wired gaming mice. The most typical cause was due to tension on the cord causing the mouse to drift slightly; almost imperceptibly, but enough for it to register as movement in Windows. The extra slick pads on the bottom of gaming mice make this far more likely. I actually use a vertical mouse now, and turn it on its side so that the optical sensor can't reflect off any surface to prevent unwanted movement during video streaming and when gaming with a controller to prevent this from happening.
You can perform a test by placing a coin or some other object underneath one side of the mouse or even directly under the optical sensor in the center to physically prevent it from being able to move, then test to see if the issue still occurs. If it does, then it must be a software/driver/OS issue, and if it does not, then it must be that the mouse is shifting slightly when not being used.